ISC Model Paper on Biotechnology 2024–25 (PDF)

Question 1

(I)

When performing the Western blotting technique, scientists use certain proteins. What type of proteins do scientists use in this procedure? (Reminder)

[1]

(iii)

A forensic scientist discovered a tiny blood spot at a crime scene. The sample was subjected to 10 PCR cycles for 40 minutes. Calculate how many DNA copies would be present at the end. (Application)

[1]

(iii)

Which nitrogen base is NOT present in the genetic material of a eukaryotic cell? (Reminder)

[1]

(A)

Cytosine

(B)

Guanine

(C)

Thymine

(D)

Uracil

(iv)

The following proteins with given molecular weight are subjected to gel electrophoresis.

Write the order in which these proteins are isolated in a gel.

(Analysis)

[1]

(v)

Give a reason for each of the following points: (Understanding)

(A)

A good vector for rDNA technology must have at least one selectable marker.

[1]

(B)

Continuous culture is preferable to batch culture.

[1]

from (vi)

The base sequence in one of the DNA strands is 5' – TAG CAT GAT – 3'.

(A)

Write the base sequence of the complementary strand. (Analysis)

[1]

(B)

Explain the basic complementarity rule. (Reminder)

[1]

(vii)

Look at the following figure and answer the following questions:

Figure 1

(A)

Identify Figure 1. Where is this structure located? (Remember)

[1]

(B)

What is its significance for a prokaryotic and a eukaryotic organism? (Understanding)

[1]

(viii)

Answer the following questions.

(A)

EMBL expand. (Recall)

[1]

(B)

What is the variation in the length of DNA fragments due to inherited differences in highly repetitive DNA, known as? (Understanding)

[1]

from (ix)

Below are two statements labelled 'Claim' and 'Reason'. Read the two statements carefully and choose the correct option.

Claim: The Trp operon is an inducible operon.

Reason: Tryptophan inhibits the process of lactose formation in the Trp operon. (Understanding)

[1]

(A)

Both the claim and the reason are true and the reason is the correct explanation for the claim.

(B)

Both the claim and the reason are true, but the reason is not the correct explanation for the claim.

(C)

The claim is true and the reasoning is false.

(D)

Both the claim and the reason are false.

(X)

Below are two statements labelled 'Claim' and 'Reason'. Read the two statements carefully and choose the correct option.

Claim: In gel electrophoresis, molecules are separated according to their charge-to-mass ratio.

Reason: The higher the charge of a molecule, the greater its mass. (Analysis)

[1]

(A)

Both the claim and the reason are true and the reason is the correct explanation for the claim.

(B)

Both the claim and the reason are true, but the reason is not the correct explanation for the claim.

(C)

The claim is true and the reasoning is false.

(D)

Both the claim and the reason are false.